Feeding device



R. M. BA RTH Jan. 11, 1955 1 N v E NTO R fiafif/l/ Baa/vet BY ATTORNEY United States Patent FEEDING DEVICE Robert Menning Barth, Pelham Manor, N.

Price-Driscoll Corporation, ration of New York Y., assignor to New York, N. Y., a corpo- The present invention relates generally to material measuring machines. In particular, it relates to machines for dispensing measured quantities of material from a source thereof into containers therefor. More specifically, the present invention relates to dispensing machines of the pressure type, that is, to machines including a hopper, a vertically arranged discharge tube mounted at the bottom of the hopper, and a pressure means associated with the discharge tube. In these mechanisms, the material flows or drops by gravity from the hopper into the tube, and as the pressure means operate, the material is forced down through the bottom of the tube into the container. With the hopper full, and a constant flow of material into the discharge tube from above, it will be obvious that the time the pressure is applied will determine the amount of material discharged.

Mechanisms of this general type have proven quite satisfactory but for the matter of dripping from the bottom of the discharge tube when the pressure is released. It will be readily understood that free flowing material will simply run down the discharge tube, and that heavier viscous liquids will also drip to some extent, thereby interfering with the measuring function of the machine. Various expedients have been devised, as drip plates, and the like, to overcome the problem, but these expedients necessitate costly additions to the machine and they are generally suitable for only one type of material, with other expedients required for another type of material.

The main object of the present invention, therefore, is the provision of a material measuring machine of the type described having means to prevent dripping from the discharge tube component when the pressure is released.

Another object of the present invention is the provision of a baffle plate within the discharge tube.

Still another object of the present invention is the provision of a pressure-responsive bafile plate within the discharge tube and adjacent the lower end thereof.

Still another object of the present invention is the provision of a baflle plate within the discharge tube of yieldable, flexible material, as rubber, synthetic rubber, relatively stiff leather and the like.

Still another object of the present invention is the provision of an imperforate baflle plate within the discharge tube, which baffle plate normally closes off the tube when the pressure is released, but which will yield to the pressure of the material moving down the tube to permit said material to pass between the periphery of the yielding battle and the discharge tube walls.

Other, further and more specific objects of my invention will in part be apparent and in part specifically pointed out in the following description of an illustrative embodiment thereof, wherein the pressure means comprises a twisted auger, it being understood that this type of pressure means is exemplary and that the scope of the present invention is to be limited only by the claims annexed hereto.

In the drawings annexed hereto and forming a part hereof,

Figure 1 is a vertical section, partly in elevation, through one form of apparatus constructed according to and embodying the present invention;

Figure 2 is a vertical sectional view of another embodiment of the present invention; and

Figure 3 is a vertical sectional view of still another embodiment thereof.

The hopper, into which the material to be dispensed 2,699,272 Patented Jan. 11, 1955 is loaded in bulk, is indicated generally by the reference numeral 10; it being further understood that the particular hopper 10 shown is merely illustrative and that the size and shape may be varied.

An elongated vertically arranged, circular-section discharge tube 12 is secured to the bottom of hopper 10, in communication therewith, into which the material from the hopper will fiow by gravity. Axially disposed within tube 12, is a pressure means, for example, an elongated twisted auger 14 with a track 17 of such diameter as to make rotating wiping contact with the interior of the tube. Auger 14 is of such length that the bottom end 16 thereof is spaced adjacent to and slightly upwards of the bottom and exit end 18 of tube 12. The upper end 20 of auger 14 is connected to means (not shown) for imparting rotary movement thereto. On counter-clockwise rotation of the auger 14, the blade 15 thereof will urge the material in the spiral track 17 down. through tube 12 towards the exit end 18 thereof. I provide a circular baffle plate 22 and secure same to the lower end 16 of auger 14 by a screw bolt 24, positioning a washer 26 between auger end 16 and head 25 of bolt 24. Plate 22 is of such yicldable, flexible material as to respond to the pressure exerted by the material being forced down tube 12 by bowing downwardly at the outer edge thereof to permit the material to flow between the tube wall and the downbent edge of the plate 22. Washer 26 functions to limit the extent of yield of plate 22 and may be made of smaller or larger diameter for such purpose, the larger diameter washer-as will be obvious-limiting the yieldability of plate 22 to a greater extent than a small diameter washer. The plate 22 thus defines a normally closed check valve which responds to the pressure of the material advanced by the auger 14 to effect an open position only during such pressure.

When auger 14 stops rotating, the pressure on plate 22 is relaxed and the plate will thereupon bend back to original position and bear against the inside of tube 12 to close off the flow of material. It has been found that plates of natural or synthetic rubber, or of elastomeric plastics, or of leather or similar material, are well adapted for the purposes of my invention, the desiderata in this connection being the ability of the material of which the plate is made to respond to positive pressure of the material under advancing movement of the auger blade to bend away from the tube wall, and to return to initial positioning against the tube wall, on cessation of the advancing pressure when the auger is stopped.

While I have shown and described hereina'bove a simple twisted auger as the pressure means, other, different, and more complicated pressure means may be employed within the scope hereof.

The diameter of baflle plate 22 is preferably equal to or slightly greater than the internal diameter of tube 12. For practical purposes, I have found that my baflle plate being treated will prevent dripping or leakage of the materials. The plate 22 illustrated herein is shown of exaggerated size in diameter with respect to the internal diameter of tube 12, it being readily understood that the degree of flexibility of plate 22 may be varied as the flow characteristics of the materials being dispensed differ. The variance may be achieved by the use of diiferent diameter washers or by the use of different material for the plate.

In Figure 2 of the drawings, there is illustrated another embodiment of the present invention, differing from the preferred embodiment only in that the plate 22a is of slightly smaller diameter than the inner diameter of the tube 12, whereas in the preferred embodiment the plate 22 is of slightly greater diameter than the inner diameter of the tube 12. In all other respects, this embodiment is identical to that above described, and in the drawing like numbers designate like parts.

Similarly, in Figure 3, there is illustrated still another embodiment of the present invention, differing from the previously described embodiments only in that the diameter of the plate 22b is substantially equal to the inner diameter of the tube 12.

It is a feature of my invention that the balfle plate 3 22 is spaced upward of the bottom 18 of tube 12. This spacing prevents scattering of the material after it passes bafl le plate 22, while permitting ready access of the bottom 16 of auger 14 when it is desired to change or replace the baflle plate.

Having described my invention, what I desire to claim and secure by Letters Patent is:

1. In a feeding device, the combination of an elongated tube, and a twisted auger mounted to rotate within the tube to feed material therethrough and to discharge it therefrom, the twisted auger and tube forming a spiral passageway, said auger terminating above the lower end of the tube and having an imperforate unitary baflle plate secured to the bottom of the auger and rotatable therewith substantially completely closing the passageway above the lower end of the tube, said plate being bendable downwardly in response to pressure from above and away from the interior of the tube, and means to limit the extent of bending of the plate.

2. In the combination of claim 1, wherein the limiting means comprise a washer of rigid, inflexible material below the baffle plate.

3. A material feeding device comprising a tube, a rotatable feed screw coaxially disposed in said tube, said feed screw having a lead end, a check valve mounted on 25 and adjacent the lead end of said feed screw and cooperating with the walls of said tube substantially to seal said tube, said check valve being normally closed and adapted to be urged to an open position by the axial pressure exerted thereon by said material while being advanced through said tube by said feed screw.

4. A material feeding device in accordance with claim 3, wherein said check valve comprises a disc of resilient flexible material.

5. A material feeding device in accordance with claim 4, wherein said disc is of slightly lesser diameter than the internal diameter of said tube.

6. A material feeding device in accordance with claim 4, wherein said disc is of greater diameter than the internal diameter of said tube.

7. A material feeding device in acordance with claim 4, wherein said disc is of a diameter substantially equal to the internal diameter of said tube.

8. A material feeding device in accordance with claim 3, wherein said check valve comprises a circular concaveconvex member of resilient flexible material the concave face of said circular member facing the direction of advance of said material.

9. A material feeding device in accordance with claim 3, wherein said tube and feed screw are vertically disposed and a hopper is provided in communication with the upper end of said tube.

References Cited in the file of this patent UNITED STATES PATENTS 621,612 Mattingly Mar. 21, 1899 723,072 Thom Mar. 17, 1903 1,356,999 Hyland Aug. 24, 1920 1,828,317 Clapp Oct. 20, 1931 2,428,995 Rogers Oct. 14, 1947 

